Abx II (lecture) Flashcards Preview

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Flashcards in Abx II (lecture) Deck (49):
1

What is the MoA of linezolid?

Bind to 50s of bacterial tRNA, preventing 70s formation

2

What is the spectrum of Linezolid?

Broad G + specific

3

What is the indication of Linezolid use?

Multi drug resistant strains

4

What is the mechanism of linezolid resistance?

Mutation of the 50s subunit preventing linezolid binding

5

What consideration is related to linezolid use with andrenergics, serotonergics and high tyramine intake (wine, cheese, and picked meats)?

Enhanced effects may result

6

What are two drugs are considered tetracyclines (other than tetracycline of course)?

Doxycycline and Minocycline

7

What is the mechanism of tetracyclines?

Bind the 30s subunit

8

What is the spectrum of tetracyclines?

Broad, mostly G +

9

What Rx is indicated in Lyme disease?

Doxy

10

How does milk influence tetracycline uptake?

Cations hinder

11

What are two absolute contraindications of tetracycline use?

Pregnancy and under 8 y.o.

12

What are the three mechanisms of tetracycline resistance?

Efflux pump
Tet-O: Ribosome protecting proteins
Enzymatic inactivation

13

What is the MoA of tigecycline?

Bind the 30s subunit

14

What is the spectrum of tigecycline?

Broad G + and G - anaerobe and aerobes

15

What "-cycline" is safe for use in renal failure and mild hepatic failure?

Tigecycline

16

What is the MoA of tigecycline (2) resistance?

TetX inactivation
AcrAB efflux

17

Streptomycin, gentamicin, neomycin, kanamycin and spectinomycin are all examples of what class of Abx?

Aminoglycosides

18

What is the MoA of aminoglycosides?

Bind 30s subunit and initiate premature termination

19

What is the spectrum of aminoglycosides?

Broad G - aerobics

20

What are the 4 main adverse effects of aminoglycosides?

Nephrotoxic
Ototoxic
Curare-like muscular blockade
Nerve dysfunction

21

With which Abx group are aminoglycosides synergistic?

B-lactams

22

What are the 2 mechanisms of amino glycoside resistance?

Enzyme inactivation
Decreased permeability to inner membrane

23

What is the MoA of chloramphenicol?

Prevent transferase on the 50s subunit

24

What is the spectrum of chloramphenicol?

Broad G -, most anaerobes

25

How is chloramphenicol metabolized?

Hepatic inactivation and renal excretion

26

What are the clinical uses of chloramphenicol?

Limited: typhoid, bacterial meningitis, anaerobe infections, rickettsial

27

What is the MoA of chloramphenicol toxicity?

Mitochondrial 70s ribosome inhibition

28

What is the concern with administration of chloramphenicol to neonates?

Gray baby syndrome (40% fatal)

29

What is the mechanism of resistance with chloramphenicol and in what bacteria (2 genera) is this a primary concern?

Decrease membrane permeability
Enzyme inactivation
Salmonella and Shigella

30

What drug classification do erythromycin, clarithromycin, and azithromycin fall under?

Macrolides

31

What is the spectrum of macrolides?

G + >> G -

32

What is the DoC of sinusitis and mild pneumonia?

Azithromycin

33

How are microlides excreted?

Mainly biliary

34

What macrolide is contraindicated in pregnancy, which is used?

Erythromycin is contraindicated
Azithromycin is used

35

What are the mechanisms (4) of resistance to macrolides?

ATP-dependent efflux
MLSB decreased binding
esterase hydrolysis
Decreased RNA binding

36

What drug is indicated for B. fragilis, Peptococcus, and Clostridium?

Clindamycin

37

What are the routes of clindamycin administration?

All: oral, topical, IM or IV (fro serious infections)

38

What are the 3 sites of clindamycin adverse effects?

neuromuscular transmission inhibition
GI:
- Life threatening pseudomembranous enterocolitis
- C. difficile overgrowth
- Diarrhea
Skin: Rash (esp with HIV and AIDS pts.)

39

What is the benefit of clinamycin over macrolides?

No ATP dependent efflux

40

What class of Abx ends in "-pristin"?

Streptogramins

41

What is the DoC for vancomycin-resistant F. faecium and S. aureus and Strep pyogenes skin infections?

Streptogramins

42

How are quinupristin and dalfopristin synergistic?

dalf enhances quin binding, which inhibits translocation

43

What is a special consideration of streptogramin administration?

5% dextrose only over 1 hr

44

How do streptogramins effect liver metabolism?

CYP3A4 inhibitor

45

What are the 3 mechanisms of streptogramin resistance?

ATP-dependent efflux
MLSB mutations fo rRNA
Lactonase and acetyl transferase

46

What is the first line drug for UTI?

Nitrofurantoin

47

What may nitrofurantoin induce in G6PD?

Hemolytic anemia

48

What is a special consideration of nitrofurantoin used during pregnancy?

Safe during first 6 months

49

Can nitrofurantoin be used during kidney failure?

NO